NXP Semiconductors
PCF8579
LCD column driver for dot matrix graphic displays
Tfr
VDD
V2
ROW 1 V3
R1 (t) V4
V5
VLCD
ROW 2
R2 (t)
VDD
V2
V3
V4
V5
VLCD
COL 1
C1 (t)
VDD
V2
V3
V4
V5
VLCD
COL 2
C2 (t)
VDD
V2
V3
V4
V5
VLCD
Voper
Vstate 1(t)
0.261 Voper
0V
0.261 Voper
Voper
Vstate 2(t)
Voper
0.478 Voper
0.261 Voper
0V
0.261 Voper
0.478 Voper
Voper
Fig 7.
Vstate1(t) = C1(t) − R1(t).
V-----o---n--(--R---M-----S--) = 1-- + ---------8----–-----1------= 0.430
Voper
8 8( 8 + 1)
Vstate2(t) = C2(t) − R2(t).
V-----o---f-f---(-R----M----S---) =
Voper
----2-8--(-(------8-8----–+----1-1--)-)---2- = 0.297
LCD drive mode waveforms for 1:8 multiplex rate
PCF8579_5
Product data sheet
Rev. 05 — 11 May 2009
state 1 (OFF)
state 2 (ON)
dot matrix
1:8 multiplex rate
msa840
© NXP B.V. 2009. All rights reserved.
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